The ultimate mineral

There are now 6.5 billion people living on the Earth. They use about 26 trillion tonnes of water a year for everything from irrigation and drinking to steel-making and washing their cars. By contrast, they use “only” about 4 billion tonnes of oil a year. So, although most water isn't traded, it is a more significant commodity than oil even if the sums of money for which it changes hands are smaller. This means water is a mineral in two senses. It makes up a goodly percentage of the Earth's crust and takes part in Earth's natural processes, and it has immense value to people, making it an “economic mineral” as well as a geological one.

How much water are people using? Like every other resource, rich people get through more of the stuff than the poor. In Africa, each person uses on average 254 cubic metres a year, but in Western Europe, the figure is 1280 cubic metres. In South America, it is 478 cubic metres, and in North and Central America, 1881 cubic metres. Asia and the former USSR are somewhere in between at 519 and 713 cubic metres respectively. (These figures and some of what follows comes with thanks from data gathered by the University of Michigan.)

A clearer way to think of it is to consider how much of the world's accessible water we are using. As we have seen, most water on the Earth is too salty to drink and most of the rest is inaccessible. But even this understates the problem. Huge amounts of fresh water flow along the Amazon but there is almost nobody there to drink it. The same applies to the big rivers that flow into the Arctic. By contrast, the Colorado River in the US is so heavily used that its mouth has dried up. In most years, no water arrives there.

It seems that all the worlds plants and forests get through about 70,000 cubic kilometres of water per year, and that agriculture and forestry account for about a quarter of this.

At the same time, the rivers and other watercourses of the world drain about 41,000 cubic kilometres a year of water. But about 70 percent of it is inaccessible except to ecotourists and scattered human populations. Of the remaining 30 percent, over half is being captured for human use, according to Sandra Postel ot the Global Water Policy Project. She adds that about two-thirds of this water is used to irrigate crops. Changing food tastes and population growth will increase the pressure to use more water in this way. More dams might add a little to the available supply but as we have seen, the hydrological cycle is a closed system where the total amount of water does not change.

Water wars

In some parts of the world, water is already politically hot, and nowhere more so than in the Middle East. It undoubtedly plays a major role in the conflict between Israel and its neighbours, including Jordan and Palestine. A substantial aquifer lies below the west bank of the Jordan which Israel has been accused of depleting. Certainly people in Israel, both Jews and Arabs, use more water, mainly for agriculture, than their neighbours. Israeli exports include fruit and cotton, both water-intensive crops. Irrigation for cotton-growing, as we have seen, has already been responsible for the destruction of the Sea of Aral. Recent reports suggest that water levels in the Sea of Galilee are heading the same way. If the water levels fall to a critical level, lower-lying water that is dangerously saline may be drawn to the surface and damage the lake for fishing, water supply and other uses.

The aquifer in question is one of the most extraordinary known to geology. While the water table normally follows the ground level, this one dives from 400m above sea level to 400m below it in the space of 30km, between the heights near Jerusalem and the depths of the Dead Sea. Part of the problem is that traditional agriculture in the area depended on the “upper aquifer” of the Judea area. This aquifer is separated by an aquitard – a band of impermeable rock – from the much larger lower aquifer below it.

The upper aquifer has sufficed for millennia to keep crops watered and people refreshed. At a reasonable rate of use, it can be replenished by rainwater and melting snow. The lower one can only be accessed by high-technology drilling. It contains ancient “fossil” water that can only be replaced over geological time. Using it up is like depleting an oil reserve. The same pressures are driving squabbles over other great rivers. The names of the Tigris and the Euphrates are among the most resonant of any rivers. They were the great watercourses of ancient Babylon and now of Iraq. But they also water Turkey and Syria, and are important to the Kurdish people who live across the regions frontiers.

There has been a persistent failure to agree on the division of the precious water of these rivers. Turkey has announced plans for the Great Anatolian Project, involving 22 dams and 19 hydroelectric power stations on their upper reaches, which would have damaging effects on the water flow lower down.

The Marsh Arabs as seen in 1974. The value of their culture and habitat is now more likely to be appreciated than it was in the past.

At the mouths of the Tigris and Euphrates is another long-running political crisis, concerning the future of a large area of wetland and of the Marsh Arabs who live there. The former regime of Saddam Hussein used drainage as a form of environmental warfare against the Marsh Arabs, building dams on both rivers to reduce the water flow to the marshes. But even in their previous form, the marshes were artificial, depending upon human maintenance of their drainage systems. Despite efforts to restore the marshes, less than 5 percent are left today, and most of the Marsh Arabs have been forced to leave.

The idea of “reclaiming” the marshes was in the minds of politicians long before Saddam came along. It was developed by a British civil engineer, Frank Haigh, in a report to the Iraqi government in 1951. His intention was to capture the water in the marshes, and the land they occupy, for agricultural production, in the era before such an environment was regarded as worth protecting in its own right.

Many of the same debates surround the Nile. Although everyone knows that Egypt is “the gift of the Nile”, the river actually flows through ten countries, as befits the worlds longest watercourse. Its use is governed by a 1929 treaty. Even Britain signed it, as a major colonial power of the time. The treaty has come under pressure because it essentially prevents anyone upstream of Egypt from using any significant amount of its water.

People as far away as Tanzania are supposed to get Egyptian consent to use Nile water to irrigate their fields. The discussions have been marked by many threats to withdraw from the treaty. But it it is abolished, the agreement that replaces it will need to be carefully crafted. Demand for water is growing all along the Nile and it is possible, as we shall see later, that the basic shape of the Nile system will be altered by climate change.

These are only a few of the worlds water conflicts. Others affect the Ganges – between India and Bangladesh – and the Mekong, involving Vietnam, Thailand, Laos and Cambodia. But the highest-profile water disputes are all going on in the Middle East, and there are two reasons for this. One is that the area is an arid one where population growth, changing agricultural practices and other pressures are leading to growing demands for a scarce resource. The problem may be eased if new technology can reduce demand for water, or make more appear by producing affordable methods of desalinating sea water.

But perhaps the real issue is that an area that has poor political institutions which are unable to solve international, or indeed internal, disputes lacks the machinery to resolve an issue such as water. Rivers go where they want and have no interest in boundaries. But in Europe, rivers such as the Rhine wander from country to country, or form international frontiers, with little controversy. Indeed, their management often provides a good example of international co-operation. Nor do Canada and the United States rattle their missiles to assert rights over the Great Lakes.

Perhaps the political activists and journalists who like to talk about “water wars” have missed the point. Water is routinely used as a weapon. This tactic is threatening because it attacks people, their food supplies and their entire environment at the same time. But an area that has proper governments and working diplomacy can solve these problems without conflict. The World watch Institute in Washington DC has found that water disputes are usually resolved peacefully. Perhaps fittingly for the world's most important commodity, says the Institute, water negotiations are often among the most successful and conflict-free of human disputes.